INTRODUÇÃO: 50-86% dos pacientes recidivam a hepatite autoimune (HAI) após a suspensão do tratamento imunossupressor. A manutenção da imunossupressão em longo prazo diminui o risco de recidiva, entretanto é necessário ajuste da dose/suspensão do tratamento em 10-30%, em razão do maior risco de neoplasias e infecções. O difosfato de cloroquina (CQ) é droga imunomoduladora que foi utilizada anteriormente em monoterapia para manutenção da remissão da HAI com diminuição da recidiva quando comparada com controle histórico. O objetivo desse estudo foi investigar a eficácia e segurança do CQ na manutenção da remissão em estudo duplo cego e randomizado e avaliar se há um subgrupo com maior benefício ao seu uso. METODOLOGIA: 61 pacientes com diagnóstico provável ou definitivo de HAI em remissão histológica, 90,1% HAI tipo 1; 23% com reatividade do anti-SLA/LP, 56,6% com fibrose avançada (F3/4) à inclusão no estudo, mas com doença hepática compensada, foram randomizados de forma duplo cego e aleatória para receber CQ 250 mg/d ou placebo, durante 36 meses ou até recidiva da doença. No primeiro mês a droga foi utilizada em combinação com a imunossupressão que induziu remissão; com posterior desmame semanal da prednisona, suspensão imediata da azatioprina e manutenção do CQ/placebo até 36 meses. As curvas de sobrevida livre de recidiva foram estimadas pelo método de Kaplan-Meyer e comparadas pelo teste de Log-Rank; as razões de risco e seus respectivos intervalos de confiança foram estimados por regressão simples de Cox. Na regressão múltipla foram avaliadas co-variáveis clinicamente relevantes para recidiva. Para investigar o subgrupo com maior benefício, as interações entre a droga e reatividade de autoanticorpos e perfil de HLA foram analisadas por regressão múltipla de Cox. As variáveis categóricas foram comparadas pelo teste exato de Fisher e as quantitativas pelo teste-t ou teste de Mann-Whitney. Foi considerado estatisticamente significante um valor de p < 0,05. RESULTADOS: 31 pacientes receberam CQ e 30 placebo. Não houve diferenças entre os grupos em relação aos achados clínicos, laboratoriais, histológicos e perfil de HLA. A sobrevida livre de recidiva foi significativamente maior no grupo CQ quando comparada ao placebo (59,3% X 19,9%, p=0,039). Após a suspensão da medicação ao término do estudo, houve 41,6% de recidiva no grupo CQ e 0% no placebo. Na regressão simples de Cox, os fatores associados com recidiva da HAI foram uso placebo, reatividade do anticorpo anti-SLA/LP, perfil de HLA DR3 e DR8. Na regressão múltipla, o uso de placebo (razão de risco de 2,4[IC 95%:1,05- 5,5], p=0,039) e reatividade do anticorpo anti-SLA/LP (razão de risco= 5.4 [IC 95%:1,91-15,3], p=0,002) associaram-se a maior risco de recidiva. Não foi possível definir subgrupo de maior benefício com uso de CQ no que se refere à reatividade do anti-SLA/LP ou perfil de HLA, embora a recidiva tenha ocorrido em 100% dos pacientes anti-SLA/LP(+) no grupo placebo e 50% no grupo CQ. No grupo CQ, 54,8% apresentaram efeitos colaterais, com suspensão da droga em 19,3%. Os efeitos colaterais mais comuns foram prurido e hiperpigmentação cutânea. CONCLUSÕES: O CQ reduziu com segurança o risco de recidiva de HAI, mas não foi possível definir subgrupo com maior benefício com essa medicação / INTRODUCTION: 50-86% of patients relapse autoimmune hepatitis (AIH) after immunosuppressive treatment withdrawal, with a higher risk of progression to liver cirrhosis, death due to liver disease and liver transplantation. The maintenance of long-term immunosuppression decreases the risk of relapse, however, treatment dose adjustment and/or interruption is required in 10-30%, with increased risk of neoplasias and infections. Chloroquine diphosphate (CQ) is an immunomodulatory drug used previously in monotherapy to maintain AIH remission with a decrease risk in relapse rates when compared to a historical control. The aims of this study were to investigate the efficacy and safety of CQ in the maintenance of remission in a double-blind and randomized study, and to evaluate if there is a subgroup with a greater benefit of its use. METHODS: 61 patients with probable or definitive diagnosis of AIH in histological remission, 90.1% type 1; 23% with anti-SLA / LP seropositivity, 56.6% with advanced fibrosis [F3 / 4] at inclusion in the study and with compensated liver disease were randomized double-blindly to receive either CQ 250 mg/day or placebo for 36 months or until relapse. In the first month, the drug was used in combination with the immunosuppressive regimen that induced the remission; with subsequent weekly weaning of prednisone, immediate withdrawal of azathioprine and maintenance of CQ/placebo for up to 36 months. Recurrence-free survival curves were estimated by the Kaplan-Meyer method and compared by the Log-Rank test; the hazard ratios and their respective confidence intervals were estimated by simple Cox regression. Clinically relevant covariables for relapse were re-evaluated bymultiple Cox regression. To investigate the existence of a subgroup with a greater benefit, interactions between the drug and autoantibody reactivity and HLA profile were analyzed by the Cox multiple regression. Categorical variables were compared by Fisher\'s exact test and the quantitative by the t-test or Mann- Whitney test. A p value of < 0.05 was considered statistically significant. RESULTS: 31 patients received CQ and 30 placebo. There were no differences between the two groups in relation to clinical, laboratory, histological and HLA profiles. Relapse-free survival was significantly higher in the CQ group when compared to placebo (59.3% X 19.9%, p=0.039). After antimalarial withdrawal at the end of the study, there was 41.6% relapse in the CQ group and 0% in the placebo. In the Cox simple regression, factors associated with AIH relapse were placebo use, anti-SLA/LP seropositivity, and HLA DR3 and DR8 profiles. In multiple regression, placebo use (Hazard Ratio = 2.4 [95% CI: 1.05-5.5], p = 0.039) and anti-SLA/LP seropositivity (Hazard Ratio = 5.4 [95% CI: 1.91-15.3], p = 0.002) were associated with a higher risk of relapse. It was not possible to define a subgroup with a greater benefit of CQ with respect to anti-SLA/LP positivity or HLA profile, although all anti-SLA/LP(+) patients in placebo group relapsed, compared to 50% in CQ group. In the CQ group, 54.8% had side effects, but 19.3% had drug withdrawal. The most common side effects were pruritus and cutaneous hyperpigmentation. CONCLUSIONS: Chloroquine safely reduced the risk of relapse of AIH, but it was not possible to define a subgroup with greater benefit with medication use

INTRODUÇÃO: 50-86% dos pacientes recidivam a hepatite autoimune (HAI) após a suspensão do tratamento imunossupressor. A manutenção da imunossupressão em longo prazo diminui o risco de recidiva, entretanto é necessário ajuste da dose/suspensão do tratamento em 10-30%, em razão do maior risco de neoplasias e infecções. O difosfato de cloroquina (CQ) é droga imunomoduladora que foi utilizada anteriormente em monoterapia para manutenção da remissão da HAI com diminuição da recidiva quando comparada com controle histórico. O objetivo desse estudo foi investigar a eficácia e segurança do CQ na manutenção da remissão em estudo duplo cego e randomizado e avaliar se há um subgrupo com maior benefício ao seu uso. METODOLOGIA: 61 pacientes com diagnóstico provável ou definitivo de HAI em remissão histológica, 90,1% HAI tipo 1; 23% com reatividade do anti-SLA/LP, 56,6% com fibrose avançada (F3/4) à inclusão no estudo, mas com doença hepática compensada, foram randomizados de forma duplo cego e aleatória para receber CQ 250 mg/d ou placebo, durante 36 meses ou até recidiva da doença. No primeiro mês a droga foi utilizada em combinação com a imunossupressão que induziu remissão; com posterior desmame semanal da prednisona, suspensão imediata da azatioprina e manutenção do CQ/placebo até 36 meses. As curvas de sobrevida livre de recidiva foram estimadas pelo método de Kaplan-Meyer e comparadas pelo teste de Log-Rank; as razões de risco e seus respectivos intervalos de confiança foram estimados por regressão simples de Cox. Na regressão múltipla foram avaliadas co-variáveis clinicamente relevantes para recidiva. Para investigar o subgrupo com maior benefício, as interações entre a droga e reatividade de autoanticorpos e perfil de HLA foram analisadas por regressão múltipla de Cox. As variáveis categóricas foram comparadas pelo teste exato de Fisher e as quantitativas pelo teste-t ou teste de Mann-Whitney. Foi considerado estatisticamente significante um valor de p < 0,05. RESULTADOS: 31 pacientes receberam CQ e 30 placebo. Não houve diferenças entre os grupos em relação aos achados clínicos, laboratoriais, histológicos e perfil de HLA. A sobrevida livre de recidiva foi significativamente maior no grupo CQ quando comparada ao placebo (59,3% X 19,9%, p=0,039). Após a suspensão da medicação ao término do estudo, houve 41,6% de recidiva no grupo CQ e 0% no placebo. Na regressão simples de Cox, os fatores associados com recidiva da HAI foram uso placebo, reatividade do anticorpo anti-SLA/LP, perfil de HLA DR3 e DR8. Na regressão múltipla, o uso de placebo (razão de risco de 2,4[IC 95%:1,05- 5,5], p=0,039) e reatividade do anticorpo anti-SLA/LP (razão de risco= 5.4 [IC 95%:1,91-15,3], p=0,002) associaram-se a maior risco de recidiva. Não foi possível definir subgrupo de maior benefício com uso de CQ no que se refere à reatividade do anti-SLA/LP ou perfil de HLA, embora a recidiva tenha ocorrido em 100% dos pacientes anti-SLA/LP(+) no grupo placebo e 50% no grupo CQ. No grupo CQ, 54,8% apresentaram efeitos colaterais, com suspensão da droga em 19,3%. Os efeitos colaterais mais comuns foram prurido e hiperpigmentação cutânea. CONCLUSÕES: O CQ reduziu com segurança o risco de recidiva de HAI, mas não foi possível definir subgrupo com maior benefício com essa medicação / INTRODUCTION: 50-86% of patients relapse autoimmune hepatitis (AIH) after immunosuppressive treatment withdrawal, with a higher risk of progression to liver cirrhosis, death due to liver disease and liver transplantation. The maintenance of long-term immunosuppression decreases the risk of relapse, however, treatment dose adjustment and/or interruption is required in 10-30%, with increased risk of neoplasias and infections. Chloroquine diphosphate (CQ) is an immunomodulatory drug used previously in monotherapy to maintain AIH remission with a decrease risk in relapse rates when compared to a historical control. The aims of this study were to investigate the efficacy and safety of CQ in the maintenance of remission in a double-blind and randomized study, and to evaluate if there is a subgroup with a greater benefit of its use. METHODS: 61 patients with probable or definitive diagnosis of AIH in histological remission, 90.1% type 1; 23% with anti-SLA / LP seropositivity, 56.6% with advanced fibrosis [F3 / 4] at inclusion in the study and with compensated liver disease were randomized double-blindly to receive either CQ 250 mg/day or placebo for 36 months or until relapse. In the first month, the drug was used in combination with the immunosuppressive regimen that induced the remission; with subsequent weekly weaning of prednisone, immediate withdrawal of azathioprine and maintenance of CQ/placebo for up to 36 months. Recurrence-free survival curves were estimated by the Kaplan-Meyer method and compared by the Log-Rank test; the hazard ratios and their respective confidence intervals were estimated by simple Cox regression. Clinically relevant covariables for relapse were re-evaluated bymultiple Cox regression. To investigate the existence of a subgroup with a greater benefit, interactions between the drug and autoantibody reactivity and HLA profile were analyzed by the Cox multiple regression. Categorical variables were compared by Fisher\'s exact test and the quantitative by the t-test or Mann- Whitney test. A p value of < 0.05 was considered statistically significant. RESULTS: 31 patients received CQ and 30 placebo. There were no differences between the two groups in relation to clinical, laboratory, histological and HLA profiles. Relapse-free survival was significantly higher in the CQ group when compared to placebo (59.3% X 19.9%, p=0.039). After antimalarial withdrawal at the end of the study, there was 41.6% relapse in the CQ group and 0% in the placebo. In the Cox simple regression, factors associated with AIH relapse were placebo use, anti-SLA/LP seropositivity, and HLA DR3 and DR8 profiles. In multiple regression, placebo use (Hazard Ratio = 2.4 [95% CI: 1.05-5.5], p = 0.039) and anti-SLA/LP seropositivity (Hazard Ratio = 5.4 [95% CI: 1.91-15.3], p = 0.002) were associated with a higher risk of relapse. It was not possible to define a subgroup with a greater benefit of CQ with respect to anti-SLA/LP positivity or HLA profile, although all anti-SLA/LP(+) patients in placebo group relapsed, compared to 50% in CQ group. In the CQ group, 54.8% had side effects, but 19.3% had drug withdrawal. The most common side effects were pruritus and cutaneous hyperpigmentation. CONCLUSIONS: Chloroquine safely reduced the risk of relapse of AIH, but it was not possible to define a subgroup with greater benefit with medication use

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Les sélénoprotéines sont des protéines auxquelles des sélénocystéines, soit le 21e acide aminé, sont incorporées durant leur traduction. Plus précisément, la sélénocystéine (Sec) est un dérivé métabolique de la sérine, mais structurellement équivalent à une cystéine dont on a remplacé l'atome de soufre par du sélénium. Elle se distingue des autres acides aminés puisqu’elle possède sa propre synthétase qui sert à convertir la sérine en Sec alors que le résidu est déjà fixé à l’ARNt. La position d’une Sec sur l’ARNm est indiquée par le codon UGA étant habituellement un signal STOP introduisant le concept de recoding. Grâce à une machinerie métabolique spécifique à l'ARNtSec et à la présence d’un SecIS (Selenocystein Insertion Sequence) sur l’ARNm, ce codon permet la présence d'une Sec dans la protéine. Il est connu que la synthèse débute avec l’acétylation de l’ARNt[Ser]Sec par la seryl-ARNt synthétase (SerRS) afin de donner la seryl-ARNt[Ser]Sec. Cette dernière est subséquemment phosphorylée par l’O-phosphoséryl-ARNt[Ser]Sec kinase (PSTK) qui donnera l’O-phosphoséryl-ARNt[Ser]Sec. Par la suite, un complexe de plusieurs protéines et cofacteurs, agissant comme machinerie pour l’incorporation des Sec durant la traduction, s’associe avec l’ARNt[Ser]Sec puis l’ARNm et, finalement, les composantes du ribosome. Parmi ces protéines, SepSecS catalyse l’étape finale de la synthèse des Sec en convertissant le O-phosphoseryl-ARNt[Ser]Sec en selenocysteinyl-ARNt[Ser]Sec utilisant le sélénophosphate comme source de sélénium. Des études récentes montrent que l’association avec SECp43 serait nécessaire pour que SepSecS joue son rôle et soit ségrégée au noyau pour s’associer à la machinerie de biosynthèse des sélénoprotéines, soit le complexe moléculaire qui reconnaît le codon UGA. Parmi les protéines de la machinerie de biosynthèse des sélénoprotéines que nous avons analysées, il y a eEFSec, RPL30, SPS2, SPS1, SBP2 et NSEP1. Nos résultats d’analyse de la dynamique de l’interaction entre les constituants de la machinerie de biosynthèse et d’incorporation des Sec, confirment plusieurs données de la littérature, mais remettent en question le modèle jusqu’à maintenant établi. Une meilleure compréhension de la dynamique des interactions entre ses constituants et la régulation de cette dynamique permet d’émettre des hypothèses quant au rôle de la machinerie de biosynthèse des sélénoprotéines et de l’importance de sa complexité. Nous avons analysé les interactions in vivo dans des cellules HEK293T au moyen de la technique de Protein-Fragment Complementation Assay (PCA) en couplant, par un clonage moléculaire, les gènes de chacune des protéines d’intérêt avec des fragments des gènes de la protéine luciférase (hRluc). Nous avons ainsi réalisé une fusion en N-terminal et en C-terminal des fragments de luciférase pour chacune des protéines d’intérêt. Puis, nous avons analysé la dynamique des interactions avec les composantes de la machinerie de biosynthèse des Sec. D’autres travaux seront essentiels afin de bâtir sur les résultats présentés dans cette recherche. / Selenoproteins are proteins that incorporate selenocysteines, which is called the 21st amino acid, during their translation. Specifically, selenocysteine (Sec) is a metabolic derivate of serine, which is structurally equivalent to Cys except for replacement of sulfur with an atom of selenium in the δ-position. It differs from other amino acids since a unique synthetase converts the serine into Sec while the residue is already attached to the tRNA. The codon for Sec on the mRNA is a UGA codon that is usually a STOP signal, introducing the concept of "recoding". Through a specific metabolic machinery for the tRNASec and the presence of a SecIS (Selenocysteine Insertion Sequence) on the mRNA, this codon allows the incorporation of the Sec into the protein. However, the mechanism of biosynthesis of this amino acid and its incorporation into proteins is not well understood. It is known that the synthesis starts with the acetylation of tRNA[Ser]Sec by seryl-tRNA synthetase (SerRS) to give the seryl-tRNA[Ser]Sec. The latter is subsequently phosphorylated by the O-phosphoseryl-tRNA[Ser]Sec kinase (PSTK) which will generate the O-phosphoseryl-tRNA[Ser]Sec. Subsequently, a large complex of several proteins and cofactors acting as machinery for incorporation of Sec during translation, associates with tRNA[Ser]Sec and the mRNA and finally, the components of the ribosome. Among these proteins, SepSecS catalyzes the final step in the biosynthesis of Sec converting O-phosphoseryl-tRNA[Ser]Sec into selenocysteinyl-tRNA[Ser]Sec using monoselenophosphate as a source of selenium. Recent studies showed that the association with SECp43 would be required for SepSecS to play its role to segregate into the nucleus to be associated with the machinery that recognizes the UGA codon. Among the proteins of the biosynthesis machinery of selenoproteins that we analyzed, there are eEFSec, RPL30, SPS2, SPS1, SBP2 and NSEP1. Results of analysis of the dynamics of the interaction between the components of the Sec biosynthetic machinery confirm some data from the literature, but conflict with the model so far established. A better understanding of the dynamics of interactions between its constituents and the reaction of this process would allow us to make assumptions about the role of the biosynthetic machinery of selenoproteins and the importance of its complexity. We analyzed the dynamics of interaction in vivo in HEK293T cells using a Protein-Fragment Complementation Assay (PCA) based on a humanized Renilla luciferase (hRLuc) by coupling, by molecular cloning, genes encoding each protein of interest with gene encoding fragments of the luciferase protein (hRluc). We have thus achieved an expression of fusion of N-terminal and C-terminal fragments for each luciferase protein of interest. Then, we analyzed the dynamics of the interaction with the components of the Sec biosynthetic machinery. Further work will be essential to build on the results presented in this research.

Les sélénoprotéines sont des protéines auxquelles des sélénocystéines, soit le 21e acide aminé, sont incorporées durant leur traduction. Plus précisément, la sélénocystéine (Sec) est un dérivé métabolique de la sérine, mais structurellement équivalent à une cystéine dont on a remplacé l'atome de soufre par du sélénium. Elle se distingue des autres acides aminés puisqu’elle possède sa propre synthétase qui sert à convertir la sérine en Sec alors que le résidu est déjà fixé à l’ARNt. La position d’une Sec sur l’ARNm est indiquée par le codon UGA étant habituellement un signal STOP introduisant le concept de recoding. Grâce à une machinerie métabolique spécifique à l'ARNtSec et à la présence d’un SecIS (Selenocystein Insertion Sequence) sur l’ARNm, ce codon permet la présence d'une Sec dans la protéine. Il est connu que la synthèse débute avec l’acétylation de l’ARNt[Ser]Sec par la seryl-ARNt synthétase (SerRS) afin de donner la seryl-ARNt[Ser]Sec. Cette dernière est subséquemment phosphorylée par l’O-phosphoséryl-ARNt[Ser]Sec kinase (PSTK) qui donnera l’O-phosphoséryl-ARNt[Ser]Sec. Par la suite, un complexe de plusieurs protéines et cofacteurs, agissant comme machinerie pour l’incorporation des Sec durant la traduction, s’associe avec l’ARNt[Ser]Sec puis l’ARNm et, finalement, les composantes du ribosome. Parmi ces protéines, SepSecS catalyse l’étape finale de la synthèse des Sec en convertissant le O-phosphoseryl-ARNt[Ser]Sec en selenocysteinyl-ARNt[Ser]Sec utilisant le sélénophosphate comme source de sélénium. Des études récentes montrent que l’association avec SECp43 serait nécessaire pour que SepSecS joue son rôle et soit ségrégée au noyau pour s’associer à la machinerie de biosynthèse des sélénoprotéines, soit le complexe moléculaire qui reconnaît le codon UGA. Parmi les protéines de la machinerie de biosynthèse des sélénoprotéines que nous avons analysées, il y a eEFSec, RPL30, SPS2, SPS1, SBP2 et NSEP1. Nos résultats d’analyse de la dynamique de l’interaction entre les constituants de la machinerie de biosynthèse et d’incorporation des Sec, confirment plusieurs données de la littérature, mais remettent en question le modèle jusqu’à maintenant établi. Une meilleure compréhension de la dynamique des interactions entre ses constituants et la régulation de cette dynamique permet d’émettre des hypothèses quant au rôle de la machinerie de biosynthèse des sélénoprotéines et de l’importance de sa complexité. Nous avons analysé les interactions in vivo dans des cellules HEK293T au moyen de la technique de Protein-Fragment Complementation Assay (PCA) en couplant, par un clonage moléculaire, les gènes de chacune des protéines d’intérêt avec des fragments des gènes de la protéine luciférase (hRluc). Nous avons ainsi réalisé une fusion en N-terminal et en C-terminal des fragments de luciférase pour chacune des protéines d’intérêt. Puis, nous avons analysé la dynamique des interactions avec les composantes de la machinerie de biosynthèse des Sec. D’autres travaux seront essentiels afin de bâtir sur les résultats présentés dans cette recherche. / Selenoproteins are proteins that incorporate selenocysteines, which is called the 21st amino acid, during their translation. Specifically, selenocysteine (Sec) is a metabolic derivate of serine, which is structurally equivalent to Cys except for replacement of sulfur with an atom of selenium in the δ-position. It differs from other amino acids since a unique synthetase converts the serine into Sec while the residue is already attached to the tRNA. The codon for Sec on the mRNA is a UGA codon that is usually a STOP signal, introducing the concept of "recoding". Through a specific metabolic machinery for the tRNASec and the presence of a SecIS (Selenocysteine Insertion Sequence) on the mRNA, this codon allows the incorporation of the Sec into the protein. However, the mechanism of biosynthesis of this amino acid and its incorporation into proteins is not well understood. It is known that the synthesis starts with the acetylation of tRNA[Ser]Sec by seryl-tRNA synthetase (SerRS) to give the seryl-tRNA[Ser]Sec. The latter is subsequently phosphorylated by the O-phosphoseryl-tRNA[Ser]Sec kinase (PSTK) which will generate the O-phosphoseryl-tRNA[Ser]Sec. Subsequently, a large complex of several proteins and cofactors acting as machinery for incorporation of Sec during translation, associates with tRNA[Ser]Sec and the mRNA and finally, the components of the ribosome. Among these proteins, SepSecS catalyzes the final step in the biosynthesis of Sec converting O-phosphoseryl-tRNA[Ser]Sec into selenocysteinyl-tRNA[Ser]Sec using monoselenophosphate as a source of selenium. Recent studies showed that the association with SECp43 would be required for SepSecS to play its role to segregate into the nucleus to be associated with the machinery that recognizes the UGA codon. Among the proteins of the biosynthesis machinery of selenoproteins that we analyzed, there are eEFSec, RPL30, SPS2, SPS1, SBP2 and NSEP1. Results of analysis of the dynamics of the interaction between the components of the Sec biosynthetic machinery confirm some data from the literature, but conflict with the model so far established. A better understanding of the dynamics of interactions between its constituents and the reaction of this process would allow us to make assumptions about the role of the biosynthetic machinery of selenoproteins and the importance of its complexity. We analyzed the dynamics of interaction in vivo in HEK293T cells using a Protein-Fragment Complementation Assay (PCA) based on a humanized Renilla luciferase (hRLuc) by coupling, by molecular cloning, genes encoding each protein of interest with gene encoding fragments of the luciferase protein (hRluc). We have thus achieved an expression of fusion of N-terminal and C-terminal fragments for each luciferase protein of interest. Then, we analyzed the dynamics of the interaction with the components of the Sec biosynthetic machinery. Further work will be essential to build on the results presented in this research.